What it is

Sales tax registration is the act of formally signing up with a state’s tax authority — usually called the department of revenue (DOR) — to obtain authority to collect sales tax. The output of a successful registration is your sales tax permit, the license that lets you legally collect tax from buyers and remit it to the state. <!– src: https://www.avalara.com/us/en/learn/guides/small-business-faq/sales-tax-registration-101.html –>

Registration is the step that follows nexus. Once you have a connection to a state — physical presence such as an office, employees, or inventory, or economic nexus from sales that cross the state’s threshold — you’re required to register before you start collecting. <!– src: https://www.avalara.com/blog/en/north-america/2018/12/sales-tax-registration-what-you-need-to-know.html –>

You can register two ways: directly with each individual state’s DOR, or — for the states that participate — through the Streamlined Sales Tax Registration System (SSTRS), which lets you register in many states with a single application. <!– src: https://www.streamlinedsalestax.org/for-businesses/sales-tax-registration-sstrs/registration-faq –>

Why it matters to a multi-state seller

For a seller operating in one state, registration is a one-time errand. For a multi-state e-commerce or wholesale business, it’s a recurring project: every time you cross a new state’s nexus threshold, a fresh registration obligation is created. Miss it, and the state can hold you liable for tax you should have been collecting all along — the registration is what puts you on the right side of the line.

This is where the Streamlined Sales Tax option earns its keep. The Streamlined Sales and Use Tax Project (SSTP) began in March 2000 to ease the compliance burden of selling across many states. <!– src: https://www.salestaxinstitute.com/sales_tax_faqs/streamlined_sales_tax_project_sstp –> Through the SSTRS you can register in all participating states, or a selected subset, with one application that asks for less information than registering with each state separately. As of August 1, 2025, there are 23 full member states plus Tennessee as an associate member. <!– src: https://www.in.gov/dor/i-am-a/business-corp/sales-tax/streamlined-sales-tax/ –>

Worked example

Say your brand has just crossed economic nexus thresholds in Indiana, Wisconsin, and Texas, and now needs to register in all three.

• Indiana and Wisconsin are both Streamlined full member states, so you can register for both — along with the other 21 SST states — in a single SSTRS application. Indiana, for example, then sends an SST Welcome Letter with its state-specific details. <!– src: https://www.in.gov/dor/i-am-a/business-corp/sales-tax/streamlined-sales-tax/ –>
• Texas is not a Streamlined member, so you register directly with the Texas Comptroller of Public Accounts.

With the Streamlined route covering Indiana and Wisconsin in one filing, you’ve reduced three separate state registrations to effectively two filings — one SSTRS application and one direct Texas registration.

What you need to register

States ask for a consistent core set of information. To register — directly or through SSTRS — have ready:

• Your legal business name and entity type
• Federal Employer Identification Number (EIN)
• Business and mailing addresses
• Owner / responsible-party details
• Your NAICS or business-activity description
• The date you established nexus or expect to start making taxable sales

When you register through Streamlined, you also choose a seller model based on how you’ll file your returns. <!– src: https://www.in.gov/dor/i-am-a/business-corp/sales-tax/streamlined-sales-tax/ –> Confirm each state’s exact requirements before filing, since some states ask for additional detail.

How this connects to staying compliant

Registration is the bridge between having a tax obligation and being able to meet it. The lifecycle runs: nexus is established → you register → the state issues your sales tax permit → you collect the correct rate → you file and remit on schedule. Skip registration and you can’t legally collect, yet you still owe the tax — the worst of both worlds.

The practical discipline is timing: register in each state in the period the state expects after you cross nexus, not months later. Registering on time keeps your collection authority clean and avoids back-tax assessments.

Sources: Avalara — Sales Tax Registration FAQ: https://www.avalara.com/us/en/learn/guides/small-business-faq/sales-tax-registration-101.html Avalara — Sales tax registration: What you need to know: https://www.avalara.com/blog/en/north-america/2018/12/sales-tax-registration-what-you-need-to-know.html Streamlined Sales Tax — Registration FAQ: https://www.streamlinedsalestax.org/for-businesses/sales-tax-registration-sstrs/registration-faq Sales Tax Institute — What is the Streamlined Sales Tax Project (SSTP)?: https://www.salestaxinstitute.com/sales_tax_faqs/streamlined_sales_tax_project_sstp Indiana DOR — Streamlined Sales Tax: https://www.in.gov/dor/i-am-a/business-corp/sales-tax/streamlined-sales-tax/